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<h1 class="title">beziercurve.cpp 示例文件</h1>
<span class="subtitle">scenegraph/customgeometry/beziercurve.cpp</span>
<!-- $$$scenegraph/customgeometry/beziercurve.cpp-description -->
<div class="descr"> <a name="details"></a>
<pre class="cpp">

  <span class="comment">/****************************************************************************
  **
  ** Copyright (C) 2016 The Qt Company Ltd.
  ** Contact: https://www.qt.io/licensing/
  **
  ** This file is part of the demonstration applications of the Qt Toolkit.
  **
  ** $QT_BEGIN_LICENSE:BSD$
  ** Commercial License Usage
  ** Licensees holding valid commercial Qt licenses may use this file in
  ** accordance with the commercial license agreement provided with the
  ** Software or, alternatively, in accordance with the terms contained in
  ** a written agreement between you and The Qt Company. For licensing terms
  ** and conditions see https://www.qt.io/terms-conditions. For further
  ** information use the contact form at https://www.qt.io/contact-us.
  **
  ** BSD License Usage
  ** Alternatively, you may use this file under the terms of the BSD license
  ** as follows:
  **
  ** &quot;Redistribution and use in source and binary forms, with or without
  ** modification, are permitted provided that the following conditions are
  ** met:
  **   * Redistributions of source code must retain the above copyright
  **     notice, this list of conditions and the following disclaimer.
  **   * Redistributions in binary form must reproduce the above copyright
  **     notice, this list of conditions and the following disclaimer in
  **     the documentation and/or other materials provided with the
  **     distribution.
  **   * Neither the name of The Qt Company Ltd nor the names of its
  **     contributors may be used to endorse or promote products derived
  **     from this software without specific prior written permission.
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  **
  ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  ** &quot;AS IS&quot; AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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  ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.&quot;
  **
  ** $QT_END_LICENSE$
  **
  ****************************************************************************/</span>

  <span class="preprocessor">#include &quot;beziercurve.h&quot;</span>

  <span class="preprocessor">#include &lt;QtQuick/qsgnode.h&gt;</span>
  <span class="preprocessor">#include &lt;QtQuick/qsgflatcolormaterial.h&gt;</span>

  BezierCurve<span class="operator">::</span>BezierCurve(<span class="type"><a href="qquickitem.html">QQuickItem</a></span> <span class="operator">*</span>parent)
      : <span class="type"><a href="qquickitem.html">QQuickItem</a></span>(parent)
      <span class="operator">,</span> m_p1(<span class="number">0</span><span class="operator">,</span> <span class="number">0</span>)
      <span class="operator">,</span> m_p2(<span class="number">1</span><span class="operator">,</span> <span class="number">0</span>)
      <span class="operator">,</span> m_p3(<span class="number">0</span><span class="operator">,</span> <span class="number">1</span>)
      <span class="operator">,</span> m_p4(<span class="number">1</span><span class="operator">,</span> <span class="number">1</span>)
      <span class="operator">,</span> m_segmentCount(<span class="number">32</span>)
  {
      setFlag(ItemHasContents<span class="operator">,</span> <span class="keyword">true</span>);
  }

  BezierCurve<span class="operator">::</span><span class="operator">~</span>BezierCurve()
  {
  }

  <span class="type">void</span> BezierCurve<span class="operator">::</span>setP1(<span class="keyword">const</span> <span class="type"><a href="../qtcore/qpointf.html">QPointF</a></span> <span class="operator">&amp;</span>p)
  {
      <span class="keyword">if</span> (p <span class="operator">=</span><span class="operator">=</span> m_p1)
          <span class="keyword">return</span>;

      m_p1 <span class="operator">=</span> p;
      <span class="keyword">emit</span> p1Changed(p);
      update();
  }

  <span class="type">void</span> BezierCurve<span class="operator">::</span>setP2(<span class="keyword">const</span> <span class="type"><a href="../qtcore/qpointf.html">QPointF</a></span> <span class="operator">&amp;</span>p)
  {
      <span class="keyword">if</span> (p <span class="operator">=</span><span class="operator">=</span> m_p2)
          <span class="keyword">return</span>;

      m_p2 <span class="operator">=</span> p;
      <span class="keyword">emit</span> p2Changed(p);
      update();
  }

  <span class="type">void</span> BezierCurve<span class="operator">::</span>setP3(<span class="keyword">const</span> <span class="type"><a href="../qtcore/qpointf.html">QPointF</a></span> <span class="operator">&amp;</span>p)
  {
      <span class="keyword">if</span> (p <span class="operator">=</span><span class="operator">=</span> m_p3)
          <span class="keyword">return</span>;

      m_p3 <span class="operator">=</span> p;
      <span class="keyword">emit</span> p3Changed(p);
      update();
  }

  <span class="type">void</span> BezierCurve<span class="operator">::</span>setP4(<span class="keyword">const</span> <span class="type"><a href="../qtcore/qpointf.html">QPointF</a></span> <span class="operator">&amp;</span>p)
  {
      <span class="keyword">if</span> (p <span class="operator">=</span><span class="operator">=</span> m_p4)
          <span class="keyword">return</span>;

      m_p4 <span class="operator">=</span> p;
      <span class="keyword">emit</span> p4Changed(p);
      update();
  }

  <span class="type">void</span> BezierCurve<span class="operator">::</span>setSegmentCount(<span class="type">int</span> count)
  {
      <span class="keyword">if</span> (m_segmentCount <span class="operator">=</span><span class="operator">=</span> count)
          <span class="keyword">return</span>;

      m_segmentCount <span class="operator">=</span> count;
      <span class="keyword">emit</span> segmentCountChanged(count);
      update();
  }

  <span class="type"><a href="qsgnode.html">QSGNode</a></span> <span class="operator">*</span>BezierCurve<span class="operator">::</span>updatePaintNode(<span class="type"><a href="qsgnode.html">QSGNode</a></span> <span class="operator">*</span>oldNode<span class="operator">,</span> UpdatePaintNodeData <span class="operator">*</span>)
  {
      <span class="type"><a href="qsggeometrynode.html">QSGGeometryNode</a></span> <span class="operator">*</span>node <span class="operator">=</span> nullptr;
      <span class="type"><a href="qsggeometry.html">QSGGeometry</a></span> <span class="operator">*</span>geometry <span class="operator">=</span> nullptr;

      <span class="keyword">if</span> (<span class="operator">!</span>oldNode) {
          node <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qsggeometrynode.html">QSGGeometryNode</a></span>;
          geometry <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qsggeometry.html">QSGGeometry</a></span>(<span class="type"><a href="qsggeometry.html">QSGGeometry</a></span><span class="operator">::</span>defaultAttributes_Point2D()<span class="operator">,</span> m_segmentCount);
          geometry<span class="operator">-</span><span class="operator">&gt;</span>setLineWidth(<span class="number">2</span>);
          geometry<span class="operator">-</span><span class="operator">&gt;</span>setDrawingMode(<span class="type"><a href="qsggeometry.html">QSGGeometry</a></span><span class="operator">::</span>DrawLineStrip);
          node<span class="operator">-</span><span class="operator">&gt;</span>setGeometry(geometry);
          node<span class="operator">-</span><span class="operator">&gt;</span>setFlag(<span class="type"><a href="qsgnode.html">QSGNode</a></span><span class="operator">::</span>OwnsGeometry);
          <span class="type"><a href="qsgflatcolormaterial.html">QSGFlatColorMaterial</a></span> <span class="operator">*</span>material <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qsgflatcolormaterial.html">QSGFlatColorMaterial</a></span>;
          material<span class="operator">-</span><span class="operator">&gt;</span>setColor(<span class="type"><a href="../qtgui/qcolor.html">QColor</a></span>(<span class="number">255</span><span class="operator">,</span> <span class="number">0</span><span class="operator">,</span> <span class="number">0</span>));
          node<span class="operator">-</span><span class="operator">&gt;</span>setMaterial(material);
          node<span class="operator">-</span><span class="operator">&gt;</span>setFlag(<span class="type"><a href="qsgnode.html">QSGNode</a></span><span class="operator">::</span>OwnsMaterial);
      } <span class="keyword">else</span> {
          node <span class="operator">=</span> <span class="keyword">static_cast</span><span class="operator">&lt;</span><span class="type"><a href="qsggeometrynode.html">QSGGeometryNode</a></span> <span class="operator">*</span><span class="operator">&gt;</span>(oldNode);
          geometry <span class="operator">=</span> node<span class="operator">-</span><span class="operator">&gt;</span>geometry();
          geometry<span class="operator">-</span><span class="operator">&gt;</span>allocate(m_segmentCount);
      }

      <span class="type"><a href="../qtcore/qsizef.html">QSizeF</a></span> itemSize <span class="operator">=</span> size();
      <span class="type"><a href="qsggeometry.html">QSGGeometry</a></span><span class="operator">::</span>Point2D <span class="operator">*</span>vertices <span class="operator">=</span> geometry<span class="operator">-</span><span class="operator">&gt;</span>vertexDataAsPoint2D();
      <span class="keyword">for</span> (<span class="type">int</span> i <span class="operator">=</span> <span class="number">0</span>; i <span class="operator">&lt;</span> m_segmentCount; <span class="operator">+</span><span class="operator">+</span>i) {
          <span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span> t <span class="operator">=</span> i <span class="operator">/</span> <span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span>(m_segmentCount <span class="operator">-</span> <span class="number">1</span>);
          <span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span> invt <span class="operator">=</span> <span class="number">1</span> <span class="operator">-</span> t;

          <span class="type"><a href="../qtcore/qpointf.html">QPointF</a></span> pos <span class="operator">=</span> invt <span class="operator">*</span> invt <span class="operator">*</span> invt <span class="operator">*</span> m_p1
                      <span class="operator">+</span> <span class="number">3</span> <span class="operator">*</span> invt <span class="operator">*</span> invt <span class="operator">*</span> t <span class="operator">*</span> m_p2
                      <span class="operator">+</span> <span class="number">3</span> <span class="operator">*</span> invt <span class="operator">*</span> t <span class="operator">*</span> t <span class="operator">*</span> m_p3
                      <span class="operator">+</span> t <span class="operator">*</span> t <span class="operator">*</span> t <span class="operator">*</span> m_p4;

          <span class="type">float</span> x <span class="operator">=</span> pos<span class="operator">.</span>x() <span class="operator">*</span> itemSize<span class="operator">.</span>width();
          <span class="type">float</span> y <span class="operator">=</span> pos<span class="operator">.</span>y() <span class="operator">*</span> itemSize<span class="operator">.</span>height();

          vertices<span class="operator">[</span>i<span class="operator">]</span><span class="operator">.</span>set(x<span class="operator">,</span> y);
      }
      node<span class="operator">-</span><span class="operator">&gt;</span>markDirty(<span class="type"><a href="qsgnode.html">QSGNode</a></span><span class="operator">::</span>DirtyGeometry);

      <span class="keyword">return</span> node;
  }

</pre>
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<!-- @@@scenegraph/customgeometry/beziercurve.cpp -->
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